Should he get out of the mushroom business after two years? Unreliable crops had just pushed his business partners out of the venture.

"I ultimately decided to stick with it," Doyle said.

He soon mastered the art of growing mushrooms.

And now his business, Forest Mushrooms, is Minnesota's biggest mushroom distributor, producing 400-500 pounds of mushrooms a day. They harvest seven days a week.

"Growing mushrooms can be a pain in the butt — that's why you don't see many businesses stay in it for very long," Doyle said. "But it can be very rewarding."

Forest Mushrooms grows its products in a renovated barn built by St. John's Abbey monks in the 1930s. They constantly funnel in oxygen, and computers keep the indoor facility at 62 degrees with 90 percent humidity.

"Fresh air is to mushrooms what fertilizers are to green plants," Doyle said.

Doyle has managed to stay profitable even with mushroom prices staying relatively the same since 1987. The price for a pound of portobello mushrooms has decreased nearly by half.

Forest Mushrooms only sells to wholesale distributors. Many of its products are in local restaurants and grocery stores. It also sells to frozen meal companies such as Stouffer's and DiGiorno.

And while Doyle spends his work hours handling mushrooms, he'll still go pick wild ones in the woods adjacent to his house.

"I see them every day but I still like go out and pick my own mushrooms," Doyle said. "It's still fun to me."